Hotaru

A Russet-haired beauty who the trio encounters while traversing a forest in Episode 2. She has full lips and burgundy lipstick. Mugen fixes her broken sandal strap and she entices him to a nearby shack. They make out, but before going further Mugen pulls away, realizing he has been poisoned. Hotaru informs him that his drink and her lipstick both contain a toxin called "one Night's Mushroom" (a mushroom known as Hitoyo-take, C. curtus; related to C. atramentaria), which is normally benign, but which, since it was consumed with alcohol, would kill him by morning. She reveals that she is working for Ryujiro and he has the antidote. With time running short, Mugen spares her life and rushes off.

This is the last we see of her. (Source: samurai-champloo.com)